Edgewise Therapeutics, a leading muscle disease biopharmaceutical company, today unveiled positive results in its sevasemten program for Becker and Duchenne muscular dystrophies.
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What is Sevasemten?
Sevasemten is an orally administered first-in-class fast skeletal myosin inhibitor designed to protect against contraction-induced muscle damage in muscular dystrophies including Becker and Duchenne. Sevasemten presents a novel mechanism of action designed to selectively limit the exaggerated muscle damage caused by the absence or loss of functional dystrophin. Its unique mechanism of action provides the potential to establish sevasemten as a foundational therapy in dystrophinopathies, either as a single agent therapy or in combination with available therapies and those in development.
Sevasemten: NSAA Scores
The MESA data demonstrated sustained disease stabilization, reinforcing prior ARCH and CANYON findings. Importantly, CANYON participants who rolled over to MESA showed increased North Star Ambulatory Assessment (NSAA) scores over 18 months (0.8 point improvement from baseline), with a trend toward improvement in placebo participants switching to sevasemten (0.2 point improvement since initiation of sevasemten). During the 18 months of sevasemten treatment, participants’ NSAA scores continued to diverge relative to the expected functional declines seen in multiple Becker natural history studies. Further, NSAA scores for ARCH participants who rolled over to MESA remained stable after three years of treatment. Sevasemten continues to demonstrate a favorable safety profile after up to three years of treatment.
Edgewise recently completed a successful Type C meeting with the U.S. Food and Drug Administration (FDA), which provided a clear path to registration of sevasemten as the first ever therapy for Becker. While the FDA deemed the CANYON data alone insufficient for an accelerated approval, the Agency reiterated that NSAA is a clinically meaningful endpoint for traditional approval. The FDA encouraged Edgewise to continue to share MESA data and natural history prospective modeling ahead of GRAND CANYON completion. Further, the FDA emphasized their support for GRAND CANYON, the ongoing global pivotal placebo-controlled cohort, and its potential as a single adequate well-controlled study to support registration. GRAND CANYON is highly powered to show a statistically significant difference in NSAA versus placebo over 18 months and is on track for topline data in the fourth quarter of 2026.
Phase 2 Duchenne Trials
The Company also announced encouraging topline data from its Phase 2 Duchenne trials, LYNX and FOX. The goals were to explore a range of doses to assess safety and identify a potentially beneficial dose for Phase 3. The trial’s dose escalation paradigm provided a three-month placebo-controlled period to evaluate biomarkers for dose selection, followed by an open label period. Across both studies, at target doses, sevasemten was well-tolerated.
LYNX is an ongoing multi-center, placebo-controlled, dose-finding Phase 2 trial to evaluate the effect of sevasemten on safety, biomarkers of muscle damage and function in four- to nine-year-old participants with Duchenne treated with sevasemten in a three-month placebo-controlled dose ranging study. Consistent observations across functional measures, including Stride Velocity 95th Centile (SV95C), NSAA and 4 stair-climb, identified a dose of 10 mg to evaluate in Phase 3.
Ages of Children Participating in the Sevasemten Clinical Trials
Similar to the LYNX design, FOX is an ongoing multi-center, placebo-controlled Phase 2 trial to evaluate the effect of sevasemten on safety, biomarkers of muscle damage and function in six- to 14-year-old participants with Duchenne who have been previously treated with gene therapy. FOX participants are on average over 10 years old and four years out from receiving gene therapy. Despite the lack of extensive natural history in Duchenne gene therapy treated boys, initial results from the FOX study indicate that sevasemten 10 mg has the potential to reduce the rate of functional decline.
“We have executed an important Phase 2 exploration of sevasemten in Duchenne,” said Kevin Koch, Ph.D., President and Chief Executive Officer. “We are encouraged by the functional response seen at the 10 mg dose and look forward to our discussions with the Agency later this year.”
The Company plans to meet with the FDA in the fourth quarter of 2025 to discuss a Phase 3 design including input on the patient population and endpoints, with plans to initiate the pivotal study in 2026. In addition, the Company plans to continue to collect longer-term open label extension data, which will provide further access to the drug to trial participants.
